Conductor stringing tool assembly



Feb. 15, 1966 E. LINDSEY CONDUCTOR STRINGING TOOL ASSEMBLY INVENTOR. A,5 4/4/0557 Filed Jan. 10, 1964 United States Patent 3,235,228 CONDUCTORSTRINGING TOOL ASSEMBLY L. E. Lindsey, 222 Vista, Pasadena, Calif. FiledJan. 10, 1964, Ser. No. 336,898 21 Claims. (Cl. 254-1343) This inventionrelates to means for installing conductors along power lines and moreparticularly to an improved stringing tool assembly designed to besupported quickly and detachably in a temporary manner on the outer endof pole-type insulators and employed to facilitate pulling a conductorinto position along the pole line and for then transferring theconductor into the insulator clamp before thestringing tool is detachedfor reuse.

The present invention has particular utility in connection withinsulators known as pole mounted, i.e. an insulator projecting generallyhorizontally from the side of the pole and having conductor clampingmeans at its outer terminal end. The installation of conductors along apole line utilizing this type of insulator has presented troublesomeproblems and several designs have been proposed in attempts to resolvethe problems but each has serious shortcomings and disadvantagesobviated by the present invention. t is desirable that the stringingtool include means for quickly, easily and safely attaching the same tothe insulator while leaving the conductor clamp unobstructed and free,to receive the conductor. The stringing tool must not place undue strainon the insulator itself and should provide adequate provision forguiding the conductor around both inside and outside bends lengthwise ofthe pole line. Inside bends are those in which the conductor bendsinwardly toward the pole and place the insulator under compression,whereas ourside bends are those in which the conductor bends away fromthe pole thereby tending to place the insulator under tension.

It is therefore a primary purpose of the present invention to provide arugged, simple,.lightweight-unitary stringing tool assembly designed tobe rigidly but detachably secured to the terminal end of a pole-typeinsulator without need for tools.

Another object of the invention is to provide a unitary stringing toolassembly that can be easily secured to the terminal of a pole-typeinsulator by snap-action means designed to lock the tool positively inplace thereon. Another object of the invention is the provision of astringing tool assembly utilizing a sheave rotating about sheaverotating in a plane transversely of the insulator closely beside itsouter end and tiltable latera ly to a position readily transferring theconductor into the insulator clamping means.

Another object of the invention is the provision of a stringing toolassembly utilizing a sheave rotating about an axis generally alignedwith the insulator and having means for connecting the same to the outerend of the insulator with the plane of the sheave adjustable to tilt ineither direction from the vertical thereby to accommodate both insideand outside bends lengthwise of the pole line.

Another object of the invention is the provision of a stringing toolassembly provided with means for temporarily securing the same to theupper end of a pole-type insulator and having hand-grip means thereonfor convenience in tilting the sheave inwardly toward the insulator andin position to discharge the conductor into the seating groove of theinsulator clamping means.

These and other more specific objects will appear upon reading thefollowing specification and claims and upon considering in connectiontherewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of theinvention is illustrated:

ice

FIGURE 1 is a side elevational view, partly in section, showing apreferred embodiment of the invention stringing tool assembly mounted onthe outer end ot a pole-type insulator;

FlGURE 2 is a fragmentary sectional view taken along the broken line 2-2on FIGURE, 1 and showing eonstructional details; and

FIGURE 3 is a fragmentary elevational' view, partly in section, showingthe cable fully assembled to the insulator and the stringing tooldetached therefrom.

Referring more particularly initially to FIGURE 3, thereis shown atypical pole ill of a cross country power line having a conventionalside-mounted: Pole-line insulator 11 secured to its side by means ofthrough bolts 12;. The hardware at the outer terminal end of'insulator11 includes a unitary cap 13 and L-shaped bracket 14 having a conductorclamping unit 15 held pivotally seated therein by a pivot screw 16). It;will be understood that the clamping unit 15 includes a conductorseating or saddle member 18 provided with aligned sockets openingthrough its opposite lateral sides one of which seats over a'boss l9axially of end cap 13 and the other of which receives the reducedcylindrical end of cap screw 16. A complementally shaped upper clamphalf 21 is secured in place astride the conductor by means of cap screws22. Additionally and importantly, it is pointed out that bracket 14includes a vertically disposed reinforcing web 23 provided with anopening 24 to seat the latch plunger ofthe stringing tool as will bedescribed in detail presently.

Referring now more particularly to FIGURES 1 and 2, a preferredembodiment of the stringing tool constituting the present invention willbe described. The stringing.

tooldesignated generally 30, is a self-contained unitary device one ofwhich is required for each insulator of the pole line along which it isdesired to install a power conductor, such as the multiple strandconductor 25. Stringing tool 30 is preferably made of a suitable highstrength, light weight alloy such as a high strength aluminum alloy. Theprincipal components are cast and have the configurationillustrated inFIGURES l and 2. Thus the tool in.- cludes a hollow main body 32providedat its outer end with aligned trunnions held in assembledposition by set screws 34 and having a purpose to be explained ingreater detail presently. The portion of main body 32 between trunnions33 is hollowedout and shaped to fit loosely about the outer end ofinsulator bracket 14 and particu-. larly the head of cap screw 16. Inother words, it will be understood that the right hand end of main body32 may 'be viewed as a socket having a close telescopic fit over capscrew 16 and the shorter vertical leg of L-shaped bracket 14.

The left hand end of main body 32 is bifurcated to permit its assemblyastride the vertically disposed web portion 23 of bracket 14. One sidewall of the bifurcated portion of main body 32 is provided with a well31 r-eci procably seating a locking latchv or plunger 38 urged to itsextended position by compression spring 39. operating handle or pin 40-projects laterally from plunger 38 and downwardly through an elongatedslot inthe side wall of well 37. This slot allows handle 40 to beshifted to and fro as necessary to move latching plunger 33 into and outof latching position in opening z iof insulator bracket 14. From theforegoing and particularly FIGURE 2,.it will be understood that whenplunger 38 is in theposition there shown, stringing tool 30 is heldfirmly assembled in its operating position on insulator 11.

The other principal sub-assembly of tool .30 comprises a Y-shaped sheavesupport member 45 having aligned openings through its Y-arms 46 journalled on trunnions 33, 33. These trunnions hold Y-mem-ber 45 inassembled position for limited arcuate movement in a vertical planeabout the axis of the trunnions. Stem 48 of the Y-memher serves as thesupport for an anti-friction bearing 49 on which the grooved sheave 51Bis mounted. The bearing and sheave is held assembled to Y-stem 48 by aradial bracket member 53 held in assembled position by keeper pin 54.Bracket 53 extends along the outer face of sheave 50 and has an arcuateouter end overlying and spaced outwardly from the sheave groove. A pivotpin 56 secured in place crosswise of the outer end of bracket 53supports a safety dog 58 having an integral bail shaped operating handle59 straddling the outer end of the bracket. A torsion spring 60 mountedloosely about pivot pin 56 strongly biases safety dog 58 to thefull-line position shown in FIGURE 1 with the bight portion of operatinghandle 59 lying against bracket 53. It will be apparent that when thesafety dog is in this position conductor cable 25 is held captive withinthe sheave and cannot be dispensed therefrom until safety dog 58 ispivoted inwardly to the dot and dash open position shown in FIG. 1.

There remains to be described the latching means for lockingsheave-supporting means 45 in a desired operating position and theassociated means for selectively varying the angular-position betweenthis latch means and the sheave proper. These important features willnow be described by reference to FIGURES 1 and 2.

Normally and so long as the cable is being strung along straightsections of the power line, it is desirable that the sheave be supportedin a vertical position transversely of the end of insulator 11 as shownin full lines in FIGURE 1. However, if a pole is located at a bend inthe power line then it is desirable that the sheave be tilted, eitherinwardly or outwardly with respect to its normal vertical position,depending on whether the conductor will act to place the insulator undercompression or under tension. If an inside bend is involved then it isdesired that the top of the sheave be tilted outwardly away from theinsulator whereas if an outside bend is involved tending to place theinsulator in tension then the top of the sheave should be tiltedinwardly toward the insulator by an appropriate angle.

- To accommodate these objectives, one of the Y-arms 46 is provided withan extension to which a threaded stud 65 is held firmly secured by setscrew 66. The outer end of stud 65 projects laterally through an arcuateslot 68 formed in a latch sector 69 pivotally supported on the adjacentone of trunnions 33. It will therefore be apparent that sector 69 can bepivoted through a short are centered on trunnion 33 provided locking nut72 on stud 65 is loose. However, if this nut is tightened then thesector is held tightly clamped against arm 46 with the result thatsector 69 is constrained to pivot bodily with Y-member 45 and sheave 50.Arcuate slot 68 is sufiiciently long to permit adjustment of the sheavethrough an angle of approximately 90 degrees or 45 degrees to eitherside of its vertical position.

The means for latching sheave 50 and sector 69 immovably in a desiredposition includes a latch bolt 75 spring-pressed toward latchingposition by a compression spring 76 mounted in a well of boss 77 formingpart of main body 32. The outer end of latch 75 is further slidablysupported in an opening passing through a lug 79. When latch 75 isextended, it engages behind detent 80 carried by latch sector 69 in themanner best shown in FIGURE 1. The opposite side of detent 80 then abutsa stop 81 projecting outwardly from the side of main body 32. Latch 75is provided with an operating handle'85 conveniently positioned to begrasped by an operator when it is desired to unlatch the sheave for freepivotal movement counterclockwise about trunnions 33, it beingimpossible for the sheave to pivot counterclockwise by reason ofengagement of detent 80 with stop 81.

The operation of the described stringing tool will be quite apparentfrom the foregoing detailed description of its construction and generalpurposes. It will be unno or minimum effort by the lineman.

derstood that the unitary assemblies 30 are readily attached to theterminal end of an insulator by seating the socketed end of main body 32over the outer end of the insulator bracket 14 while holding latchplunger 38 (FIG. 3) retracted. As soon as this plunger is in alignmentwith opening 24 of bracket 14, plunger 38 is released permitting itsspring 39 to extend the plunger through the opening thereby positivelylocking the stringing tool to the insulator. Either prior to or aftermounting tool 30 on the insulator, nut 72 may be loosened and the sheavetilted clockwise or counterclockwise through an appropriate angledepending on whether the particular pole is located at an inside or anoutside curve lengthwise of the power line. Once the proper angularadjustment has been made, in accordance with the principles outlinedabove, nut 72 is firmly tightened.

The next step is to thread a leader or other tension line through thesuccessive sheaves with the far end of the line attached to theconductor to be installed. Thereafter the tension line is pulled throughthe various sheaves by suitable power winches thereby graduallyadvancing the main conductor through the sheave and lengthwise of thepower line.

As soon as the conductor has been drawn into position the lineman climbsthe pole and grasps the operating handle 85 of latch and retracts androtates handle to latch the plunger open behind boss 86. He then cangrasp safety dog handle 59 and pull this handle toward him over the topof bracket 53 with the same hand used to unlatch plunger '75. This opensthe safety dog to the dotted line position shown in FIGURE 1 followingwhich further pulling force applied to handle 59 tilts the entire sheavesub-unit about trunnions 33 until the sheave is in the conductor dumpingposition shown in FIGURE 1. At this point, the downwardly inclined sidewall of the sheave groove acts to discharge conductor 25 automaticallyinto clamping socket by gravity action and with The operator thenreleases handle 59, allowing the sheave to return to its former positionand then places clamping cap 21 in position over the firmly seatedconductor and tightens clamping cap screws 22.

Before leaving the pole the lineman grasps assembly 30 in one hand andhandle 40 of latch 13 in the other. As soon as the latter latch isretracted, the lineman can lift tool 30 from the outer end of theinsulator and lower it to the ground for re-use in the same mannerdescribed above to install further lengths of the power cable.

It is pointed out that the herein illustrated and described line-dumpingsheave is highly advantageous and operates smoothly and with a minimumexpenditure of energy to transfer a flexible line, conductor, cable orthe like from the sheave directly onto a permanent support therefor.This operation is performed quickly without need for tools of any kindand by the manual etfort of a single hand of a lineman while standing onthe pole and using his other hand to safeguard his ovm safety or forpurposes other than dumping the contents of the sheave.

While the particular conductor stringing tool assembly herein shown anddisclosed in detail is fully capable of attaining the objects andproviding the advantages hereinbefore stated, it is to be understoodthat it is merely illustrative of the presently preferred embodiment ofthe invention and that no limitations are intended to the details ofconstruction or design herein shown other than as defined in theappended claims.

I claim:

1. A stringing tool for installing power conductors between pole-mountedinsulators of the type having a conductor clamp and bracket assemblyrigidly secured to the outer end thereof, said stringing tool having amain body provided with means for detachably supporting the sametemporarily on said bracket assembly, means rotatably supporting asheave on said main body to one side of said conductor clamp and inconvenient position for transferring a conductor from said sheave intosaid clamp and leaving said stringing tool free for detachment from saidbracket assembly, means movably interconnecting said main body and saidsheave means, means for releasably locking said sheave in apredetermined plane of operation during installation of a conductor andincluding manual means for releasing said sheave for movement in adirection to facilitate transfer of a conductor from said sheave intosaid conductor clamp.

2. A conductor stringing tool as defined in claim 1 characterized inthat said means for releasably locking saidsheave in a predeterminedplane includes means for supporting said sheave selectively in any oneof a plurality of different operating planes while running a conductoralong a pole line and around both inside and outside bends. A

3. A conductor stringing tool as defined in claim 1 characterized inthat said sheave means includes a frame and axle unit for said sheave,said frame embracing a portion of the groove extending about theperiphery of the sheave and including a combined safety guard andmanipulating handle, and means normally holding said safety guard inposition to prevent sidewise loss of a conductor from the sheave grooveuntil and unless said safety guard is forcibly moved to a releaseposition.

, 4. A stringing tool assembly designed to be temporarily but detachablysupported beneath and closely opposite the conductor clamp bracket meansof an insulator of the type projecting outwardly from the side of apower line pole or the like, said tool assembly having a main bodyhaving first mounting means formed to seat axially over the outer end ofsaid insulator bracket means and second means offset laterally from theaxis of said clamp bracket means including fast-action manuallyactuatable means for rigidly holding said main body assembled to saidbracket means, sheave-mounting frame means movably supported on saidmain body having a sheave rotatably supported therein for rotation in aplane extending crosswise of the axis of said insulator and in closeproximity to the conductor clamp of said bracket means.

5. A stringing tool assembly as defined in claim 4 characterized in thatsaid manually actuatable means for holding said main body rigidlyassembled to said bracket means includes manually operable spring-biasedlock means having an end positioned to enter a juxaposed opening formedin said insulator bracket means to lock said stringing tool assembly tosaid conductor clamp bracket means.

6. A stringing tool assembly as defined in claim 4 characterized in theprovision of manually operable means cooperating with said main body andwith said sheave-mounting frame means to hold these two componentsselectively in different positions with said sheave differently inclinedwith respect to a horizontal plane through the axis of the insulator onwhich said stringing tool assembly is mounted.

7. A stringing tool assembly for use in installing a power conductorbetween generally horizontally projecting pole-type insulators of apower line, said stringing tool assembly having an elongated main bodyhaving a socket in one end to receive and seat over the outer end of aconductor supporting bracket means carried on the outer end of theinsulator, the opposite end of said main body having yoke meansstraddling the lower portion of said bracket means, latch pin meanscarried crosswise of said yoke and engageable with said bracket means tohold said main body temporarily assembled thereon, sheave mounting meansmovably secured to said main body with said sheave lying in a planeextending crosswise of and closely adjacent the outer end of saidbracket means and in position for the convenient transfer of a conductorfrom support in the sheave to a clamping posi- 6 tion overlying saidbracket means and out of contact with said stringing tool assembly.

8. A stringing tool assembly as defined in claim 7 characterized in thatsaid sheave mounting means is held assembled to said main body by pivotmeans having its axis extending horizontally crosswise of said main bodyat the end thereof remote from the dielectric of an insulator on whichsaid assembly is mounted, and means for locking said sheave mountingmeans selectively in different angular positions with said sheaveinelined to either side of its normal vertical plane of rotation.

9. A stringing tool assembly as defined in claim 7 characterized in thatsaid sheave mounting means includes an upright rigid stationary bracketon the remote face of said sheave from the insulator on which saidassembly is mounted, said rigid bracket partially embracing the entranceto the sheave groove, an L-shaped safety dog pivotally supported in theupper end portion of said rigid bracket and having spring means normallybiasing said safety dog to a closed position for blocking a conductorfrom escape laterally over one edge of saidshe'ave.

10. A stringing tool assembly as defined in claim 9 characterized inthat said safety dog includes operating handle means shaped and disposedto lie closely against said rigid bracket when said safety dog .isclosedand being pivotable to a convenient manipulating position for saidsheave mounting means when said handle is moved to open said safety dog;

11. A stringing tool assembly adapted to be latched temporarily to theconductor supporting bracket on the outer end of a non-verticallysupported insulator, said assembly comprising sheave means havingamounting yoke extending axially from one end of a shaft for said sheave,a main body member having socket means at one end seatable over theouter end of said conductor supporting bracket and provided with meansfor temporarily clamping said body member thereto, and pivot meansholding said mounting yoke and a sheave thereon assembled to said mainbody for arcuate movement between a conductor stringing position and aconductor transfer position wherein the conductor present in said sheaveis transferred onto said conductor supporting bracket in readiness to beclamped to said insulator.

12. A conductor stringing tool assembly adapted to be snapped onto andfrom the terminal end of an insulator designed to extend generallyhorizontally from a support therefor, said assembly having a sheaverotatably supported on frame means, clamping means carried by said framemeans contoured to interfit with portions of the insulator terminal endand including snap-action means for holding said assembly detachablyassembled to said terminal end without interfering with clamping aconductor to said terminal end, and releasable means selectively holdingsaid sheave in one of a plurality of desired operating planes while aconductor is being pulled into position for transfer into clampingposition on said terminal end.

13. A unitary cable stringing tool comprising a Y- shaped member havinga sheave journalled on the stem thereof, the ends of said Y -arms havingaligned openings therethrough, a mounting bracket for said stringingtool having a hollow main body adapted to be telescoped over theterminal end of an insulator, aligned trunnion means at one end of saidmain body extending through and providing a pivot support for theopenings in the outer ends of said Y-arms, latch means carried by theother end of said main body for latching said stringing tool to theterminal end of an insulator, and latch means interconnecting saidY-shaped member and said main body operable to lock said sheave and itssupporting Y-member releasably against pivotal movement about the axesof said trunnion means.

14. A. stringing tool as defined in claim 13 characterized in theprovision of adjustable means for varying the angular position of saidY-member relative to said main body existing when locked in its latchedposition.

15. A stringing tool as defined in claim 13 characterized in theprovision of stop means effective to prevent pivotal movement of saidsheave except in a predetermined direction to dump a cable seated in thesheave groove laterally therefrom and toward the end of said main bodyremote from said sheave.

16. A stringing tool as defined in claim 13 characterized in theprovision of bracket means secured to the terminal end portion of saidY-stem and keyed thereto to hold said sheave assembled thereon, saidbracket means extending radially along one face of said sheave andhaving an arcuate end overlying and spaced outwardly from the peripheryof said sheave, safety dog means pivoted to the outer end of saidbracket means and including spring means biasing the same against a stopposition wherein said safety dog means and said bracket means cooperateto hold a conductor captive on the sheave, and handle means for saidsafety dog means.

17. That improvement in means for stringing a conductor betweennon-vertically mounted pole line insulators which comprises, a unitarystringing tool having means for securing the same to a pole lineinsulator, sheave means on said tool having a sheave lying in a plane extending crosswise and adjacent the outer end of said insulator, andpivot means interconnecting said sheave means to said tool having apivot axis spaced closely beside the inner face of said sheave andadjacent the sheave axis and the axis of said insulator and permittingsaid sheave to be tilted sidewise until the groove of said sheave ispositioned to discharge a conductor riding therein out of said sheaveand onto the terminal end of the insulator on which said stringing toolis supported.

18. That improvement defined in claim 17 characterized in that saidstringing tool includes latch means normally positioned to hold saidsheave means locked against pivoting movement and being manuallyreleasable to permit the sheave means to tilt toward said insulator todump a conductor out of said sheave.

19. That improvement in tool means for facilitating stringing a flexibleline lengthwise between a plurality of permanent supports for said line,said stringing tool means comprising bracket means rotatably supportinga sheave in a generally upright operating position, means pivotallyconnected to said bracket means and pivotable about an axis disposedgenerally parallel to the plane of rotation of said sheave and to oneside thereof, said last-named means including means for detachably andtemporarily supporting said stringing tool means closely adjacent apermanent support for said flexible line and in such position thatsidewise tilting of said sheave about said pivot axis to a generallyhorizontal position is effective to dump a flexible line out of saidsheave and onto the permanent support therefor.

20. That improvement defined in claim 19 characterized in that saidstringing tool means includes means normally effective to hold saidsheave in a desired upright operating position, and handle meansoperatively connected to said sheave supporting bracket means for use inmanually pivoting the same along With said sheave into line dumpingposition.

21. That improvement defined in claim 20 characterized in the provisionof means on said stringing tool means for normally releasably lockingsaid sheave against pivotal movement about said axis.

References Cited by the Examiner UNITED STATES PATENTS 2,613,256 10/1915Thomas 254134.3 3,170,673 2/1965 McAuley 254134.3

FOREIGN PATENTS 714,317 8/1954 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

OTHELL M. SIMPSON, Examiner.

1. A STRINGING TOOL FOR INSTALLING POWER CONDUCTORS BETWEEN POLE-MOUNTEDINSULATORS OF THE TYPE HAVING A CONDUCTOR CLAMP AND BRACKET ASSEMBLYRIGIDLY SECURED TO THE OUTER END THEREOF, SAID STRINGING TOOL HAVING AMAIN BODY PROVIDED WITH MEANS FOR DETACHABLY SUPPORTING THE SAMETEMPORARILY ON SAID BRACKET ASSEMBLY, MEANS ROTATABLY SUPPORTING ASHEAVE ON SAID MAIN BODY TO ONE SIDE OF SAID CONDUCTOR CLAMP AND INCONVENIENT POSITION FOR TRANSFERRING A CONDUCTOR FROM SAID SHEAVE INTOSAID CLAMP AND LEAVING SAID STRINGING TOOL FREE FOR DETACHMENT FROM SAIDBRACKET ASSEMBLY, MEANS MOVABLY INTERCONNECTING SAID MAIN BODY AND SAIDSHEAVE MEANS, MEANS FOR RELEASABLY LOCKING SAID SHEAVE IN APREDETERMINED PLANE OF OPERATION DURING INSTALLATION OF A CONDUCTOR ANDINCLUDING MANUAL MEANS FOR RELEASING SAID SHEAVE FOR MOVEMENT IN ADIRECTION TO FACILITATE TRANSFER OF A CONDUCTOR FROM SAID SHEAVE INTOSAID CONDUCTOR CLAMP.